The present invention relates to tools for use in swaging and, more particularly, to a swaging tool for swaging axially swaged fittings.
Swaged fittings have been used for many years to connect tubes and pipes in various types of systems, including fluid systems used in the aircraft, marine, petroleum and chemical industries, as well as power transmission systems and the like. In a typical fluid system, the ends of two tubes are inserted into opposing ends of a fitting, each of which is usually in the form of a cylindrical sleeve. The fitting is then swaged with a swaging tool to produce a fluid-tight connection placing the tubes in fluid communication. This swaging operation is normally carried out by applying a radial force that radially compresses the fitting and tubing inwardly. This radial force may be applied directly by the swaging tool or indirectly by a specially shaped ring that is moved axially by the swaging tool to apply a radial force to the fitting. The invention of the present application is directed to the latter type of swaging tool designed for use with fittings having axially movable swaging rings. These fittings are referred to as axially swaged fittings.
Typical axially swaged fittings comprise a cylindrical sleeve having openings at opposite ends for receiving the ends of two tubes, with a swaging ring at each end of the sleeve. The outer surface of the sleeve and the inner surface of the swaging ring contact each other, being shaped such that axial movement of the swaging ring over the sleeve applies a radial force to the sleeve and, thus, to the tubes. Although not all fittings employ a sleeve with two swaging rings, the use of two swaging rings is preferable when it is desired, as is often the case, to join two tubes to each other.
An example of a prior art swaging tool can be seen in U.S. Pat. No. 5,592,726, which is incorporated herein by reference for all purposes. With reference to FIG. 1, which represents the tool depicted in FIG. 5 of the patent, the prior art swage tool includes a housing 11 with a cylindrical bore forming a chamber, and a piston 13, each having a jaw unit used for the axial swaging of a fitting. The piston 13 is held and carried on a stabilizing pin 15 that is conformingly received by a ram 17. The stabilizing pin and ram are held together by a spring 19. The spring, which reacts against a plug 21 that is held in place within the housing by a retainer ring 23, pushes the stabilizing pin and ram toward an end of the housing opposite the plug.
A tube 25 is inserted into a sleeve 27 with a swaging ring 29, with the sleeve being held by an outer yoke 31 on the housing and the swaging ring being adjoined by an inner yoke 33 on the piston 13. When hydraulic fluid (e.g., oil) is introduced into the housing via a port 35, the ram 17, the stabilizing pin 15 and the piston 13 translate axially through the housing together to compress the spring, causing the inner yoke to drive the swaging ring toward the outer yoke (as depicted), thereby axially swaging the sleeve onto the tube.
The ram and stabilizing pin each include a bearing 37 and 39 (respectively) to provide for smooth translation within the housing. When the stabilizing pin 15, piston 13 and ram 17 are translated by the spring into the portion of the housing near the plug, the stabilizing pin bearing 39 moves into a portion of the housing cylinder that forms a cutout within which the yoke 33 of the piston moves. To provide radial support for the stabilizing pin bearing around most of its circumference, the cutout defines lobes on either side of a narrow slot. The ram further includes a seal 41 and a seal ring 43 to prevent hydraulic fluid from seeping past the ram.
While the above-described tool has a good functional design, there are some features that would preferably be improved. For example, in assembling such a tool, each part contributes to tolerance buildup, and each area of contact between relatively moving parts is subject to wear. Furthermore, the stabilizing pin bearing is subject to wear when it is supported from less than a full 360 degrees, such as when the bearing moves within the portion of the housing forming the narrow slot.
Accordingly, there has existed a need for a swaging tool, for swaging axially swaged fittings, that has few moving parts, is lighter in weight and/or more reliable than most prior swaging tools. In various embodiments, the present invention satisfies some or all of these and other needs and provides further related advantages.